<?php if(is_active_sidebar('side_widget')){ dynamic_sidebar('side_widget'); } else { ?>

 <div class="side_widget">
  <h3 class="headline">Recent Post</h3>
  <ul>
   <?php $myposts = get_posts('numberposts=5'); foreach($myposts as $post) : ?>
   <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
   <?php endforeach; ?>
  </ul>
 </div>

 <div class="side_widget">
  <h3 class="headline">Calendar</h3>
  <?php get_calendar(true); ?>
 </div>

 <div class="side_widget">
  <h3 class="headline">Archives</h3>
  <ul>
   <?php wp_get_archives('type=monthly'); ?>
  </ul>
 </div>

 <div class="side_widget">
  <h3 class="headline">Category</h3>
  <ul>
   <?php wp_list_categories('orderby=name'); ?>
  </ul>
 </div>

<?php }; ?>